Differences in the frequency of consumption of 30 selected foods and in the estimated intake of total calories and selected nutrients in relation to alcohol drinking, tobacco smoking, and education were described using information obtained from 1,774 controls of a case-control study of digestive tract cancers conducted in northern Italy. Heavy alcohol consumption, tobacco smoking, and lower level of education were associated with a diet poorer in several aspects, including lower consumption of fresh fruit and green vegetables and higher intake of specific indicator foods, such as sausages and canned meat. For instance, the mean number of portions of fresh fruit per week was 10.5 among male nondrinkers vs. 9.0 among heavy drinkers, 10.4 among male nonsmokers vs. 8.1 among heavy smokers, and 8.8 in less educated individuals vs. 10.7 among those more educated. Consequently, intake of beta-carotene, ascorbic acid, and calcium tended to be inversely related to alcohol and tobacco and directly related to education. Most associations were stronger in males, for whom alcohol consumption was also more common in less educated individuals. Calorie intake was directly related to alcohol consumption, largely reflecting calories provided by alcohol itself. However, alcohol drinking was also directly related to fat consumption. In both sexes, there was a strong positive correlation between cigarette smoking and coffee drinking. These results provide quantitative documentation that alcohol drinking, tobacco smoking, and education, three of the major determinants of cancer risks, were also correlates of dietary patterns and, hence, may exert an important confounding or modifying effect on the diet and cancer relationship.